© 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Chapter 7A Networking and Information Systems.

© 2013 by the McGraw-Hill Companies, Inc. All rights reserved.

Chapter 7AChapter 7A

Networking and Information Networking and Information SystemsSystems

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Learning ObjectivesLearning Objectives7.17.1 Describe the benefits of using networks, the Describe the benefits of using networks, the

common types of networks, and network common types of networks, and network hardwarehardware

7.2 7.2 Define the term Define the term information systeminformation system, and list , and list the basic structural components of any the basic structural components of any

information systeminformation system7.3 7.3 Identify types of information systems, and Identify types of information systems, and

explain the basic purpose of eachexplain the basic purpose of each7.47.4 Describe fault-tolerant computing, as related Describe fault-tolerant computing, as related

to information systems, and explain the to information systems, and explain the purpose of purpose of electronic data interchangeelectronic data interchange

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Computer NetworksComputer Networks• NetworkNetwork : a set of hardware, software, and media : a set of hardware, software, and media

systems used to connect computers togethersystems used to connect computers together• Benefits of networks:Benefits of networks:

– Users easily share data, Users easily share data, programs, and hardware programs, and hardware

– Make it easy to back up dataMake it easy to back up data– Open up new ways to Open up new ways to

communicatecommunicate

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Types of NetworksTypes of Networks• Common types of networksCommon types of networks

– Local area network (LAN) Local area network (LAN) : : a data communication system a data communication system consisting of multiple devicesconsisting of multiple devices

– Wide area network (WAN) Wide area network (WAN) : : the connection of two or the connection of two or more central computers or LANsmore central computers or LANs

– Intranet Intranet : an internal version of the Internet the contains : an internal version of the Internet the contains only the company's private informationonly the company's private information

– ExtranetExtranet : : shares intranet resources with people outside of shares intranet resources with people outside of the organizationthe organization

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Network MediaNetwork Media• Network Network mediamedia are the means used to link together are the means used to link together

a computer network’s a computer network’s nodes nodes • Types of media:Types of media:

– Twisted-pair cableTwisted-pair cable: normally consists of four pairs of wires: normally consists of four pairs of wires– Coaxial cableCoaxial cable: : has two conductors with an insulator has two conductors with an insulator

betweenbetween– Fiber-optic cableFiber-optic cable: a thin strand of glass that transmits : a thin strand of glass that transmits

pulsating beams of light rather than electric currentpulsating beams of light rather than electric current– Wireless networksWireless networks: : use radio or infrared signals that travel use radio or infrared signals that travel

through the air to transmit datathrough the air to transmit data

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Network TopologiesNetwork Topologies• PacketsPackets: pieces of a message broken down in to : pieces of a message broken down in to

small unitssmall units– Data moves through the network in packetsData moves through the network in packets– Most packets have two parts:Most packets have two parts:

• HeaderHeader: : first part; contains information needed by the networkfirst part; contains information needed by the network• PayloadPayload: : the actual data being transmitted between the nodesthe actual data being transmitted between the nodes

• TopologyTopology: logical layout of the cables and devices: logical layout of the cables and devices

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Types of TopologiesTypes of Topologies• Bus topologyBus topology: arranges the network nodes in a : arranges the network nodes in a

series, linking one node to the next via a single cableseries, linking one node to the next via a single cable– A A terminatorterminator is attached at the start and end points is attached at the start and end points

• StarStar topologytopology: all nodes are connected to a hub wire : all nodes are connected to a hub wire and communicate through itand communicate through it

• Ring topologyRing topology: connects the network’s nodes in a : connects the network’s nodes in a circular chaincircular chain

• Mesh topologyMesh topology: a cable runs from every computer to : a cable runs from every computer to every other computerevery other computer

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Network HardwareNetwork Hardware• Linking devices:Linking devices:

– RepeatersRepeaters: : prevent attenuation when packets are traveling prevent attenuation when packets are traveling long distanceslong distances

– HubsHubs: : provide multiple ports for connecting nodesprovide multiple ports for connecting nodes

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Network HardwareNetwork Hardware• Linking devices:Linking devices:

– BridgesBridges: : connect two LANs connect two LANs or two segments of a LANor two segments of a LAN

– SwitchesSwitches: : devices that are devices that are aware of the exact address aware of the exact address so they can send packets so they can send packets to the correct destinationto the correct destination

– RoutersRouters: : devices that devices that store the routingstore the routinginformationinformation

– GatewaysGateways: : create create connections between connections between different types of networksdifferent types of networks

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StandardsStandards• Each LAN is governed by a Each LAN is governed by a protocolprotocol

– An agreed-upon message format for transmitting data An agreed-upon message format for transmitting data between two devicesbetween two devices

• Physical transmission standards:Physical transmission standards:– EthernetEthernet: : Most installations use an Ethernet star topology Most installations use an Ethernet star topology

with either twisted-pair or fiber-optic cableswith either twisted-pair or fiber-optic cables– FastFast EthernetEthernet: available using the same topology as : available using the same topology as

Ethernet, but can achieve speeds up to 100 MbpsEthernet, but can achieve speeds up to 100 Mbps– Gigabit EthernetGigabit Ethernet: : version of Ethernet technology that version of Ethernet technology that

supports data transfer rates of 1 gigabit per secondsupports data transfer rates of 1 gigabit per second

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Options for Data CommunicationOptions for Data Communication• Modems with telephone linesModems with telephone lines• Broadband access Broadband access

– BroadbandBroadband: : can transmit data faster than standard dial-up can transmit data faster than standard dial-up connection using a modemconnection using a modem

– Asynchronous transfer modeAsynchronous transfer mode:: a more efficient way to a more efficient way to send data over a single networksend data over a single network

• Wireless networksWireless networks– Wi-FiWi-Fi: : popular standard for wireless networkingpopular standard for wireless networking– Wireless access pointWireless access point: : where one or more computers can where one or more computers can

connect to the networkconnect to the network

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Information SystemsInformation Systems• Information systemInformation system: a system for acquiring, storing, : a system for acquiring, storing,

organizing, using, and sharing data and informationorganizing, using, and sharing data and information• Basic componentsBasic components

– Physical means for storing dataPhysical means for storing data– Physical means, methods, procedures for distributing and Physical means, methods, procedures for distributing and

sharing informationsharing information– Procedures for handling information to ensure its integrityProcedures for handling information to ensure its integrity– Rules regarding data use and distributionRules regarding data use and distribution

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Types of InformationTypes of Information• Office automation systemOffice automation system: : Uses computers and/or Uses computers and/or

networks to perform operations needed in an office networks to perform operations needed in an office environmentenvironment– Off-the-shelf applicationsOff-the-shelf applications: software available for purchase : software available for purchase

by anyoneby anyone• Transaction processing system:Transaction processing system:

system that handles the system that handles the processing and tracking processing and tracking of transactionsof transactions– TransactionTransaction: : A complete A complete

information operationinformation operation

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Types of InformationTypes of Information• Management information systemManagement information system:: set of software set of software

tools that enables managers to gather, organize, and tools that enables managers to gather, organize, and evaluate informationevaluate information

• Decision support systemDecision support system:: collects and reports certain collects and reports certain types of data to help managers types of data to help managers make better decisionsmake better decisions

• Expert systemExpert system:: type of type of information system that information system that performs analytical tasksperforms analytical tasks

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Fault-ToleranceFault-Tolerance• Mission-criticalMission-critical systems must run without failure or systems must run without failure or

with nearly instant recovery from failurewith nearly instant recovery from failure• Fault-tolerantFault-tolerant computers are able to continue computers are able to continue

operation even when components and programs failoperation even when components and programs fail– RedundantRedundant computers have multiple hardware systems computers have multiple hardware systems

performing the same task at the same timeperforming the same task at the same time– Redundant array of independent disks (RAID): Redundant array of independent disks (RAID): Storage Storage

system that links an array of disk drives so they act as a system that links an array of disk drives so they act as a single disksingle disk

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RAIDRAID• StripingStriping (or RAID 0): gives user rapid access by (or RAID 0): gives user rapid access by

spreading data across several disksspreading data across several disks• MirroredMirrored (RAID 1) system: Data written to two or (RAID 1) system: Data written to two or

more disks simultaneouslymore disks simultaneously• Striping-with-parityStriping-with-parity (RAID 5): data is spread over (RAID 5): data is spread over

multiple disks and the system stores parity multiple disks and the system stores parity information for reconstructing data if necessaryinformation for reconstructing data if necessary

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Scalable and Interoperable SystemsScalable and Interoperable Systems

• ScalabilityScalability: : The capability The capability to provide increasing to provide increasing amounts of computing amounts of computing power, storage, and power, storage, and softwaresoftware

• InteroperabilityInteroperability: : Ability of Ability of each information system each information system to work with the other to work with the other information systemsinformation systems

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DataData• Data warehousingData warehousing

– Huge data warehouses can store data from thousands or Huge data warehouses can store data from thousands or millions of transactionsmillions of transactions

• Data miningData mining– Analysis uncovers trends, opportunities, threatsAnalysis uncovers trends, opportunities, threats

• Data scrubbingData scrubbing: : – process of safeguarding against erroneous or process of safeguarding against erroneous or

duplicate dataduplicate data

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Data TransactionsData Transactions• Organizations that send large volumes of information Organizations that send large volumes of information

need a more efficient method need a more efficient method than e-mailthan e-mail

• Electronic data interchange (EDI)Electronic data interchange (EDI): : A standardized A standardized electronic transfer of information between electronic transfer of information between companies over networkscompanies over networks– Can occur over extranets or the InternetCan occur over extranets or the Internet– Not a way to transfer fundsNot a way to transfer funds